About the size of a marking pen, this non-contact tester detects AC voltages from 200 - 1000V. Featuring red and green indicators, the unit will glow green when safe, and when voltage is detected it will flash red and beep at an increasing rate as you get closer to the voltage source. It can be used for detecting live mains in outlets, power boards or insulated wiring. It also has an LED torch and a handy pocket clip. A must for every toolbox.